Nature is filled with astonishing and sometimes terrifying phenomena. Case in point: this footage of spiders seemingly raining from the sky.

Filmed in Minas Gerais in southern Brazil, these spiders are Parawixia bistriata, a rare ‘social’ spider that works together to build giant, fine webs up high.

And contrary to how it might look, don’t worry, they’re not actually raining down from above.

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In reality, these harmless orb weavers are settled in a giant, fine web that’s almost invisible to the naked eye, hunting for prey. At the end of the video you can see them moving across the web.

As apocalyptic as it might look, this phenomenon is pretty common in the area when the weather is hot and humid – it’s summer over there at the moment.

The footage was filmed by João Pedro Martinelli Fonseca, who was traveling to his grandparents’ farm in Espírito Santo do Dourado, about 250 km north-east of São Paulo, when he was “stunned and scared” to see lots of black dots in the sky, The Guardian reports.

His grandmother Jercina Martinelli, told local paper Terra Do Mandu: “There were many more webs and spiders than you can see in the video. We’ve seen this before, always at dusk on days when it’s been really hot.”

Adalberto dos Santos, a biology professor specializing in arachnology at the Federal University of Minas Gerais told The Guardianthat Parawixia bistriata work together in the evenings to build webs that can be up to 4 metres (13 feet) wide and 3 metres (9.8 feet) thick.

In the early dawn, they eat the prey capture in the net overnight – small insects and sometimes even small birds – before spending the day hidden in vegetation.

The good news is these spiders are harmless to humans – in fact they actually help us out by getting rid of insects such as mosquitoes and flies.